There are several ways to protect useful and ornamental plants against pests, disease and weeds. The simplest, yet most ineffective way is purely mechanical removal of weeds and pests. The most common method is the use of chemical control agents, because of their ease of application. However, the use of chemical agents often invokes the disadvantage of unwanted side effects which may be attributed, for example, to high toxicity or inadequate degradability, and in the case of pests, the development of resistance, often after only a short period of time.
In particular, pests such as the spider mite are particularly troublesome. Spider mites belong to the family of Acari known scientifically as Tetranychidae, and are a common form of agricultural pest which damage the foliage of plants. Two common species of spider mites are the carmine (red) spider mite (Tetranychus cinnabarinus) and the two-spotted spider mite (Tetranychus urticae), both of which can inflict damage and reduce yields of growing crops and plants.
Various miticides are presently available to combat infestations of spider mites by killing such pests. One popular miticide is dicofol, commercially available from Rohm & Haas Company of Philadelphia, Pa. under the tradename "KELTHANE". ##STR1## Another popular miticide is a micronized form of sulfur, commercially available from Cumberland International of Houston, Tex., under the tradename "SULFLOX". A third type of popular miticide is 2-(p-tert-butylphenoxy) cyclohexyl-2-propynyl sulfite, commercially available from Uniroyal Chemical, a division of Uniroyal, Inc. under the tradename "COMITE". ##STR2##
Still another commercially available miticide is sold under the tradename AVID, a spiro[11,15-methano-2H, 13H, 17H-furo[4,3,2-pq][2,6]benzodioxacyclooctadecin-13,2'-[2H]pyran], avermectin B1 derivative, available from Merck & Co., Inc. of Rahway, N.J. Yet another miticide is sold under the tradename TALSTAR, a cyclopropanecarboxylic acid, 3-(2-chloro-3,3,3-trifluoro-1-propenyl)-2,2-dimethyl-,(2-methyl[1,1'-biphe nyl]-3-yl)methyl ester, [1.alpha.,3.alpha.(Z)]-(..+-..)-, available from FMC, Philadelphia, Pa. ##STR3## Yet another product is bi-2,4-cyclopentadien-1-yl,1,1',2,2',3,3',4,4',5,5'-decachloro-or bis(pentachloro-2,4-cyclopentadien-1-yl), sold under the tradename PENTAC AQUAFLOW, available from Sandoz, Ltd., Basel Switzerland. ##STR4## And still another product is sold under the tradename SAFER soap, commercially available from Safer Inc., Newton, Mass.
While such miticides are generally effective against spider mites in the short term, spider mites reproduce rapidly, and resistant strains develop an increased tolerance of such miticides over a period of time. It is also believed that spider mites must actually come in physical contact with such miticides in order to be killed thereby. However, as compared with other agricultural pests, spider mites move relatively little, and are therefore less likely to come into physical contact with applied miticides unless relatively large amounts of such miticides are applied.
However, with all of the typical pest control methods currently in use, there is no product currently available which is environmentally safe, to which insects do not quickly develop a resistance to.